Edgar-winner Parker’s complex, ambitious, sixth and final Charlie Hood novel (after 2012’s The Jaguar) finds the affable, tireless deputy in the Los Angeles County Sheriff’s office working undercover for the Federal Bureau of Alcohol, Tobacco, and Firearms. Posing as an arms dealer named Charlie Hooper, Hood is trying to stop the flow of guns between Southern California and Mexico—and locate the elusive Mike Finnegan, a mixture of Professor Moriarty and Doctor Faustus who featured prominently in The Jaguar. Meanwhile, Bradley Jones continues to work both sides of the fence as a deputy with the sheriff’s office and as a courier for the Baja Cartel, while trying to reconcile with his pregnant wife, Erin. And Clint Wampler, a wannabe gun runner, is looking to make a score. As usual, Parker combines an artfully constructed plot with memorable prose (e.g., “the dusty burnt breath of a space heater”). This highly impressive thriller demonstrates how genre fiction can take on substantial themes in an entertaining and provocative way. Agent: Robert Gottlieb, Trident Media Group. (Apr.)